Dragon defenders are dead content, they're absolute shit. Shields are bad as well since for most things they're a lot less useful than the extra dps from dual wielding.
Use the best off hand you can, a dragon longsword off-hand is much better for your dps.
Dragon Defenders are complete garbage. I heard they were going to get an update although I can't see them worth getting ever again. Which is kind of depressing.
Yeah, its not very useful at all as there are way better items you can wear instead of it. Off-hand weapons seem to be broken at the moment anyways, atleast some of them hardly add any damage.